1. Industrial Useful Field
This invention relates to a centrifugal lock-up clutch suitable for an acceleration clutch of a stepless speed-change power transmission for use in a vehicle having a fluid coupling comprising the acceleration clutch, a forward/backward change-over mechanism coupled to a rear stage of the acceleration clutch, and a stepless speed changer coupled to a rear stage of the forward/backward change-over mechanism.
2. Prior Art and Its Problem
A centrifugal lock-up clutch has conventionally been used in an automatic transmission (U.S. Pat. No. 4305493). In this centrifugal lock-up clutch, transmission torque characteristics are changed stepwise according to an engine rotation speed, a slip is produced to decrease a transmission torque in a large load region, and a shock or torsional vibration in changing speed is absorbed conservatively by means of said slip.
For this reason, its construction becomes complicated, its manufacturing becomes difficult and a power of engine is thrown away by the amount of slip so that a vehicle fuel consumption is worsened.
The inventor made the present invention with an intention to develop a centrifugal lock-up clutch suitable for a stepless speed changer which includes no speed-change stage and does not positively generate a slip.